It was the school holidays, and a Friday lunchtime finish meant I could pack the Delica, load the children and head south to arrive in time for an evening fish.

I have been taking my eight-year-old daughter Katy on fishing trips since she could walk, and we have had an annual fishing trip to the Tekapo canals since she was five. This year my twin boys, Jack and Alfie, turned five, so it was now time for them to join us on our annual adventure.

The hydro canals are a great resource to catch fish for the table, and are ideal for keen young anglers fishing with a light tackle setup. Last year Katy and I saw someone catch a rainbow just under 20lb (9.1kg) only a few hundred metres downstream from us, and although we could not believe the size of the fish, we knew that we were in with a chance, too.

On the journey south we talked about being safe whilst fishing, but with three young children, I was well aware I needed eyes in the front, back and sides of my head. The deep, variable flows of the canals can be dangerous, especially when flowing at their peak.

We arrived at our fishing spot at 4pm, so it was out with the chairs and start setting up the rods. We had brought a varied selection of offerings, including worms, shrimps, Glo-bugs, lures and soft-baits, and each of the children had their own preference for what was going on the end of their line. Jack liked his worms, which had been enthusiastically dug from the vege garden the previous day, Katy was keen to try some of the soft-baits she'd given to me for Father's Day, whereas Alfie just wanted to start fishing as soon as possible.

Within five minutes of fishing, Jack shouted, "Fish! fish!" and Alfie immediately grabbed the net for his brother. With his rod held high, Jack guided the 2lb rainbow to the bank for me to net.

Not long after Jack was into his next rainbow, and I could not believe how quickly he was hooking them, making me curious as to his technique. I could see that once his bait settled on the bottom, he would give his reel a small erratic wind every couple of seconds, in between adjusting his drag and giving his rod a gentle lift. He was a natural and was fully in tune with his line, so any fish showing the slightest interest in his bait had no chance.

However, this technique also had the effect of getting a few snags, and every so often there would be a "Dad, I'm stuck - can you help me?"

Consequently, although I had taken a rod for myself to fish, I knew this was not an option, as I was either netting fish, clearing snags, untangling bird's nests or making food and drinks - but it was great watching the little ones really enjoying their fishing and encouraging each other.

After Jack's two fish, stomachs started to rumble, and it was time for a quick feed of noodles. This was when the questions started.

"Dad, are there any piranhas in there?"

"No, only trout and salmon."

"Are you sure? Any giant catfish?"

"I think you've been watching too many episodes of River Monsters!"

We'd just about finished our noodles when Alfie's rod started to nod and he was shouting, "I've got a fish! I've got a fish!"

His 2lb brown trout had no sooner gone into the net, when he put his rod down to run back and shovel in the last fork-full of noodles (hungry work this fishing!), before running straight away for a photo with his fish. The new excitement made everyone keen to carry on fishing.

It was just on dark when Alfie's reel went 'weeeeezzzz' and he was hooked up solidly. The fish fought strongly and big sister Katy had to help him hold his rod, as his little arms were struggling to hold on. I could see this was a good fish, and just hoped his little hand-me-down rod didn't snap!

However, all ended well, and once netted, Alfie wanted to feel the weight of the 5lb brown in the net - a new personal best for him. By the time he was ready to pose for some photos his arms were tired from reeling in the fish, but he made the effort for a solo photo before getting some help from the rest of us.

After a quick clean-up, we folded the seats down in the Delica, which were to be our beds for the night, and crawled into our sleeping bags, ready for an early start the next day.

The beeping alarm at 5.30am woke us all, and a clear starry night meant it was a cold morning. They were all keen to get fishing though, and as soon as they had their lines in the water, the kettle was on for a round of Milos to warm up.

Katy persevered with soft-baits and had a few interested fish follow close to the bank, but no hook-ups. It was a quiet morning for the others too, so the drawing and colouring books were well used before we decided to head to a different spot further down the canal, below the salmon farm, looking over to Mount Cook.

The long morning chill soon faded away, and it was time to pack away the coats and get the sunhats out. The lack of action and restless children meant we needed a break, so we drove to Tekapo for an icecream and planned our afternoon and evening fishing location.

As the children wanted to go back to our first spot, that's where we went, and just before 2pm Katy was on the board with a small rainbow.

It was then a long afternoon of questions, such as: "Where does all of the water come from?" "How does the water make electricity?" and "What is electricity for?"

"Who's hungry? I said, to which they all shouted "Me!" So it was out with the frying pan for some bacon and eggs. It was near the end of our second day fishing, the sun had just gone down, and I was finishing my cup of tea; there had been no fishing action for about four hours.

But suddenly the fish started their evening rise, including a big splash made about 50 metres downstream that also showed the long dark back of a huge fish. I thought to myself, "It would be nice to catch one of those - one day, one day!"

Ten minutes later Katy's rod gave a long slow bend. There was no bounce in the rod and I thought she'd hooked into some debris washing down the canal.

"Dad, I'm stuck - can you help me?" I thought this was telling me it was time to pack up for the night. Katy passed the rod to me to try and free it from the debris or the bottom, and I felt a strong tug, so gave it back saying, "The bottom doesn't move, start reeling in."

Later on, with Katy's little pink Shimano Lipstix rod straining, I saw a big flash of colour and said, "Look at the size of that!" and hoped the 6lb leader would hold.

However, while the fish came to the surface fairly easily, it did not want to come near the edge of the canal. A slight drag adjustment made it easier for Katy to play the fish and gain more control, but it was more the weight of the fish and not the fight that was making it difficult for her.

A few minutes later it was within five metres of the bank. By now Katy was struggling, so I told her to stop reeling and just slowly walk backwards. Alfie passed the net to me and I crept low, trying not to scare the fish into a last dash across the canal. As the fish came to the edge, I tried to scoop it into the net, but unfortunately, the net was nowhere near big enough, and the fish just rolled out and tried to swim away.

I knew that if I didn't get this fish now, the line would probably snap and I'd be cursing myself all night.

Slowly it drifted towards the bank again, so I stepped into the edge of the canal, got the head in the net so it could not swim away, and grabbed the tail. Then, with a big heave-ho out of the water it came, followed by a scramble up the bank, and it was ours.

Alfie shouted "It's humungous!" and I let out a huge "Woooo-hooo!", all of us laughing with disbelief at the size of the 17lb (7.7kg) rainbow trout.

Katy did so well to hold on tight, reel in the monster, and guide it to the bank. She said her shoulders were really sore, but it was worth it to catch a big fish. I was so proud of her. As for the boys, this was the perfect way to finish their first fishing trip to the canals, providing a magical memory that will last forever.

So after plenty of photos and a phone call to tell Mum, it was a late night before we got to sleep!